Paulson William D, Ram Sunanda J, Faiyaz Rashid, Caldito Gloria C, Atray Naveen K
Department of Medicine, Division of Nephrology and Hypertension, Louisiana State University Health Sciences Center, Shreveport, LA 71130, USA.
Am J Kidney Dis. 2002 Oct;40(4):769-76. doi: 10.1053/ajkd.2002.35688.
Although a low blood flow (Q(a)) is the most important cause of graft thrombosis, several studies have shown that Q(a) measurements do not accurately predict thrombosis. This suggests that additional variables may influence thrombosis. Identification of such variables may be essential to designing surveillance protocols that accurately predict thrombosis. In this nested case-control study, we prospectively followed 105 patients for up to 2.5 years in order to test the association of a number of variables with thrombosis. These included Q(a) (monthly by ultrasound dilution), percentage stenosis (quarterly by duplex ultrasound), mean arterial pressure (MAP), percentage ultrafiltration (%UF) during dialysis (%UF = 100[liters]/[kilogram of weight]), and other variables that defined patient and graft characteristics. Patients were divided into patent (n = 53) and thrombosed groups (n = 52), and MAP and %UF from seven consecutive dialysis sessions were analyzed. In the thrombosed group, the last session was the final session before thrombosis. A multivariable logistic regression model showed that Q(a), MAP (the predialysis average of seven sessions), and %UF (from the last session) were independently associated with thrombosis, whereas all other variables were not. The model yielded the following odds ratios for thrombosis: for a single Q(a) value (reduction of 1,000 mL/min), 12.0 (P < 0.01); for %UF (increase of 4%), 5.3 (P < 0.01); for MAP (reduction of 30 mm Hg), 4.1 (P = 0.02); and for percentage decrease in Q(a) (> or =20% versus <20%), 2.4 (P = 0.12). We conclude that in addition to Q(a), both %UF at the last session before thrombosis and average predialysis MAP from seven sessions are independently associated with thrombosis. These results help explain why Q(a) alone does not accurately predict thrombosis. A prospective study is needed to determine whether %UF at each session and a moving average MAP from seven sessions improve the prediction of thrombosis. However, it should be recognized that a large %UF is a preterminal event that likely provides too short a warning for intervention before thrombosis.
尽管低血流量（Q(a)）是移植血管血栓形成的最重要原因，但多项研究表明，Q(a)测量并不能准确预测血栓形成。这表明可能还有其他变量会影响血栓形成。识别这些变量对于设计能够准确预测血栓形成的监测方案可能至关重要。在这项巢式病例对照研究中，我们对105例患者进行了长达2.5年的前瞻性随访，以测试多个变量与血栓形成之间的关联。这些变量包括Q(a)（每月通过超声稀释法测量）、狭窄百分比（每季度通过双功超声测量）、平均动脉压（MAP）、透析期间的超滤百分比（%UF）（%UF = 100×[升数]/[体重千克数]）以及其他定义患者和移植血管特征的变量。患者被分为通畅组（n = 53）和血栓形成组（n = 52），并对连续七次透析治疗的MAP和%UF进行了分析。在血栓形成组中，最后一次治疗是血栓形成前的最后一次治疗。多变量逻辑回归模型显示，Q(a)、MAP（七次治疗的透析前平均值）和%UF（最后一次治疗的值）与血栓形成独立相关，而所有其他变量则不然。该模型得出的血栓形成比值比如下：对于单个Q(a)值（降低1000 mL/min），为12.0（P < 0.01）；对于%UF（增加4%），为5.3（P < 0.01）；对于MAP（降低30 mmHg），为4.1（P = 0.02）；对于Q(a)降低百分比（≥20% 与 <20%相比），为2.4（P = 0.12）。我们得出结论，除了Q(a)之外，血栓形成前最后一次治疗时的%UF以及七次治疗的透析前平均MAP均与血栓形成独立相关。这些结果有助于解释为什么仅Q(a)不能准确预测血栓形成。需要进行一项前瞻性研究来确定每次治疗时的%UF以及七次治疗的移动平均MAP是否能改善对血栓形成的预测。然而，应该认识到，超滤百分比过高是终末期前事件，可能在血栓形成前提供的干预预警时间过短。
